In the prior art, the propagation of electron waves in modulation doped structures is well-known. U.S. Pat. No. 4,550,330, filed Jun. 29, 1984 shows an interferometer structure wherein a bifurcated branch conductive path coplanar with a heterojunction in a semiconductor has a two-dimensional electron gas (2-DEG) formed adjacent the heterojunction so that electron waves can be launched into and travel in the 2-DEG. In addition, the reference shows a means for inducing a potential barrier such that the wavelength and phase of the electron waves transiting it are changed. In this arangement, all the electron waves which exit the potential barrier have the same wavelength and phase. There is no indication in this reference that electron waves traversing a potential barrier may be acted on in such a way that the phases and wavelengths of the exiting electron waves may be different. Similarly, in a copending application, Ser. No. 06/854,635 filed Apr. 22, 1986 and assigned to the same assignee as the present application, a tunable stub is shown in which a potential barrier is induced in an underlying heterojunction semiconductor arrangement by a gate structure, such that the wavelength and phase of electron waves transiting the barrier are all affected the same way. There is no indication in this reference that the phase and wavelength of the impinging electron wavesd may be controlled by controlling the slopes of the potential barrier at the points where the electron waves impinge.
IBM Technical Disclosure Bullentin, Vol. 31, No. 8, Jan. 1989, page 150, in an article entitled "Heterostructure Traveling Wave Transistor" by F. Fang and T. P. Smith, III, there is shown an interdigitated comb gate disposed over a 2-DEG. When the comb gate has a potential applied to it, potential barriers are induced in the underlying heterostructure such that electron waves launched in the 2-DEG encounter periodically varying potential barriers. These barriers are all aligned in such a way that electron waves transiting a given barrier all exdperience the same change in wavelength and phase across the width of the induced barrier. There is no indication in this reference of how the wavelength and phase of the electron waves may be varied across the width of a potential barrier.
It is, therefore, an object of the present invention to provide a ballistic transport semiconductor device in which a shaped electrode induces a shaped potential barrier such that electron waves transiting the potential barrier are each affected differently.
Another object is to provide a ballistic transport semiconductor or quantum mechanical effect device in which the slopese of the induced potential barrier affect different electron waves differently such that the electron waves are deflected from their original paths.
Still another object is to provide a ballistic transport semiconductor quantum mechanical device wherein gate electrodes having curved edges induce similarly curved potential barriers such that parallel electron waves impinging on the curved potential barriers are focused or diverge from their initial paths.
Yet another object is to provide a ballistic transport semiconductor quantum mechanical device wherein, relative to the path of an impinging electron wave, the slope of an induced potential barrier at the point of impingement determines the amount of deflection and, therefore, the ultimate destination of the electron wave.
These and other objects, features and advantages of the present invention will become more apparent from the following particular description of the preferred embodiments taken in conjunction with following briefly described drawings.